Effect of Wing Plates on a Multiline Ring Anchor System in Cohesive Soils

Attractive sites for offshore renewable energy facilities, such as offshore wind or wave energy systems, are often located in deep water due to stronger, more consistent resources and mitigation of aesthetic concerns. Despite improvements in the technology associated with floating offshore energy systems, the high capital cost of the support systems still remains a significant obstacle. This study presents a novel, efficient multiline ring anchor (MRA) system which can provide significant capital cost savings. A limited comparative study of the MRA to a suction caisson in soft clays shows the MRA has a clear advantage under horizontal loading, but further efficiencies may be realized by attaching wing plates to the cylindrical core of the anchor. Two-dimensional finite element analyses were conducted to understand how wing plates alter the collapse mechanism of a cylindrical anchor and to provide reliable estimates of load capacity. The studies show that the collapse mechanisms and bearing factors can be understood in terms of existing knowledge of the behavior of plate and cylindrical anchors.